1. Field of the Invention
The present invention relates generally to improvements in breast pumps and, more particularly, pertains to a new and improved method and apparatus for extracting milk from the breast.
2. Description of Related Art
Most prior art breast pumps designed for extracting milk are concerned only with controlling the rate at which a negative pressure is applied to the breast and, in some cases, the amount of negative pressure. An example of an electric breast pump which does more than this is illustrated in the U.S. Pat. No. 6,383,163 granted May 7, 2002 to two of the three named joint inventors of the present invention. The disclosure of U.S. Pat. No. 6,383,163 is expressly incorporated herein by reference.
Although the prior art breast pumps and, specifically, the prior art breast pump described and claimed in U.S. Pat. No. 6,383,163 are very effective, these prior art pumps do not contemplate controlling the refractory time of the suction cycle. The result is that the pump is not as efficient as it could be in removing the breast milk. As a result of this decreased efficiency, a longer overall pumping period is required. The longer period increases the physical demands on the user. Moreover, most prior art breast pumps only apply a suction face to the breast for expressing the mother's milk.
The present invention, on the other hand, is much more efficient than the prior art devices. The present invention allows the user to control the amount of time within a suction cycle that pressure is applied to the breast and the amount of time that no pressure is applied to the breast, independently of the frequency of the suction cycle. Control of the refractory time results in a substantial increase in the amount of milk collected over a given time period. The use of a breast cup that collapses in a progressive manner mimicking a suckling infant facilitates an efficient or comfortable expression of the mother's milk.